The present invention relates generally to a digital signal processing apparatus for processing a digital video signal and a digital audio signal and, more particularly, to a digital signal processing apparatus including an expansion processing section for extending a system bus to which a computation means is connected.
Computers (computation processing apparatuses) have been used as digital signal processing apparatuses for processing digital video signals and digital audio signals. That is, there is a tendency for computation apparatuses including computation means (CPU), input and output means, storage means, a system bus, and the like, and having the versatility to be able to perform a variety of tasks to be used as digital signal processing apparatuses.
However, when it is necessary to process video signals in real time, a conventional general-purpose computer may not necessarily be the most appropriate apparatus. The reason for this is that a general-purpose computer is not equipped with input and output means and real-time processing means dedicated solely to the processing of video signals. Thus, because of a resulting slow processing time, video signals may not be able to be processed in real time.
In order to remedy this situation, the following is conventionally performed. What is commonly referred to as an expansion slot is provided in the system bus of a computer, and a circuit board (expansion board) which enables the addition of various functions is mounted to this expansion slot. However, when complex processing is required as in a video editing operation, a plurality of circuit boards requiring a plurality of expansion slots are required. Problems may arise in the way the means for exchanging a video signal between boards is supplied.
Furthermore, in a conventional general-purpose computer, since the dimensions and method of mounting a board to an expansion slot are limited, a large circuit board having an unconventional size cannot be used, and high-speed transfer of data of video and audio signals is limited. It would therefore be beneficial to provide an improved digital signal processing apparatus that overcomes the drawbacks of the prior art.
It is therefore an object of the invention to provide an improved digital signal processing apparatus suitable for processing digital video and audio signals.
It is another object of the invention to provide an improved digital signal processing apparatus which is capable of increasing the number of expansion slots.
A further object of the invention is to provide an improved digital signal processing apparatus having a high degree of freedom in the size of circuit boards that can be mounted to expansion slots.
Still another object of the invention is to provide an improved digital signal processing apparatus that is capable of increasing the number of signal lines for video and audio signals and control signals.
Yet another object of the invention is to provide an improved digital signal processing apparatus having a high degree of freedom in the arrangement of circuit boards that can be mounted to expansion boards.
Still other objects and advantages of the invention will in part be obvious and will in part to apparent from the specification and the drawings.
Generally speaking, in accordance with the invention a system bus, computation means connected to the system bus, and a signal dedicated bus provided as a bus dedicated to video and audio signals which is adapted to be coupled with the system bus are provided.
The digital signal processing apparatus according to the invention preferably comprises an information processing section including a system bus to which computation means is connected; and an expansion processing section including a system bus for extending the above system bus, wherein the signal dedicated bus is provided within the expansion processing section. The expansion processing section is preferably provided with a power apparatus for the expansion processing section, and the power apparatus is controlled by the information processing section.
Furthermore, the signal dedicated bus preferably includes at least a video signal line, a video synchronization signal line, an audio signal line, and an audio synchronization signal line The video signal line of the signal dedicated bus preferably transmits video signals of a plurality of channels in parallel.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.